Running an App in RStudio worked yesterday morning. I didn't change anything at all but it stopped running because there was a problem with shiny (that I stupidly didn't note at the time).
I then potentially did something more stupid and updated my packages. That didn't work so I updated to latest version of r.
I have:
library(tidyverse)
library(shiny)
Loading required package: shiny
Error in read_csv("CombinedDemographics19.csv") :
could not find function "read_csv"
Thanks when I ran library(tidyverse) in a new RScript I found problems with rlang and httpuv which thanks to the trusty internet I was able to resolve.